Carbon paper



Patented Dec. 21, 1943 UNITED STATES PATEN T OFFICE Bigi-re A. Dreyfifsfiflnd. assignor to arfa A. G., Fabrik ehemlsche-teehnischer Bureanmaterialien, Pery, near Biel, Switzerland Application May 25, 1942, Serial No. 444,452' In Switzerland February 10, 1941 1 claim. (OI. 282-228) It is already known to provide the rear surface of carbon paper with a coating consisting, for instance of wax or parafiin for preventing the rolling up of the paper. But it has been found that even this kind of coating could not prevent completely the rolling action.

It was found however that the said rolling just after 'a long storing-up of the paper has completely disappeared if the carbon paper is provided with a coatng of a streaked Structure wherein the streaks run in changing directions, that is, in parane] zigzag lines.

The method of manufacturing this carbon paper according to the present invention is therefore characterized in that the scraping-tool, which in a known manner serves for applying the coating and serves atthe same'time for removing from the pap r any superfluous matter and which at its working edge is provided with a toothing, executs a reciprocating movement in its longitudinal direction. t

The toothing of the scraping tool may be I ormed in a known manner by the fact that it is enveloped with wire like a piano string the windings of the wire being close togethen By this slight toothing and the reciprocating movement of the scraper the streaked Structure of'the coating in changing directions on the backside of the paper will be produced.

A cutting of a sheet of carbon paper prepared according to the present invention has been represented by way of example in the accompanying drawing.

From this drawing representing the rear surface of a sheet of carbon paper provided with the coating it may be seen that the coating paste presents a streaked Structure constituted of nearly wave-like running parallel lines.

At the places where the scraper changes its direction streaks 2 will be formed running across the sheet and standing out clistinctly between the bevel streaking I. Therefore the user of such a carbon paper is aways easily enabled to distinguish front andrear side of a sheet of carbon paper. With the hitherto used carbon paper-s provided with a wax coating, the rear and front streaked formation, the streaks running in rows of spaced parallel lines with the lines of one row extending in theopposite direction to those of an adjacent row for reducing the likelihood of rolling of the sheet and for rendering the rear surface of the sheet clearly distinguishable from the front surface.

PIERRE A. DREYFUS. 

